1. Field of the Invention
The present invention relates to a silicon carbide manufacturing device and a method of manufacturing silicon carbide.
2. Description of the Related Art
Conventionally, a silicon carbide (SiC) manufacturing device using a gas growth method has a graphite crucible and a seed crystal disposed in the graphite crucible. A source gas of SiC is induced in the graphite crucible so that a SiC crystal grows on a surface of the seed crystal.
For example, a seed crystal J2 is disposed on an upper surface of a cylindrical graphite crucible J1, a gas-inducing pipe J3 is connected to a lower surface of the graphite crucible J1, and the source gas is induced in the graphite crucible J1 through the gas-inducing pipe J3, as shown in FIG. 7. Here, a mixed gas of silane (SiH4) and propane (C3H8) is induced as the source gas in a state where the graphite crucible J1 is heated at about 2300° C. Thereby, a SiC single crystal grows on a surface of the seed crystal J2.
The SiC manufacturing device using the gas growth method has an advantage that the source gas can be supplied for a long time. However, this SiC manufacturing device has a problem that a source material in the source gas decomposes and reacts in a temperature zone in the gas-inducing pipe J3, thereby a powder-shaped deposit (i.e., reactive deposit) J4 attaches to an inner wall of the gas-inducing pipe J3. Thus, in a case where a supplying time of the source gas becomes long, the gas-inducing pipe J3 may be clogged with the reactive deposit J4, thereby the SiC crystal may not grow, and the advantage of the gas growth method may be reduced.
For example, WO9814643 (corresponding to JP 2001-501161 A) discloses a SiC manufacturing device, in which a gas-inducing pipe has a double pipe structure. A source gas is induced from an inner pipe, and a carrier gas such as argon and helium is induced between an outer pipe and the inner pipe. Thereby, the source gas is restricted from attaching to an inner wall of the gas-inducing pipe, and a reactive deposit is restricted from growing on the inner wall of the gas-inducing pipe.
In this SiC manufacturing device, a cluster-shaped reactive deposit may be formed, and may move toward the inner wall of the gas-inducing pipe across the carrier gas. As a result, this SiC manufacturing device cannot prevent the above-described problem.
Alternatively, JP 2001-35795 A discloses a vapor-phase growth device having a scratching blade for removing a clogging on a side of an exhaust pipe, i.e., at a downstream of a portion where a vapor-phase growth is performed. Specifically, the scratching blade is attached to a rotating shaft arranged in a center portion of the exhaust pipe, and is rotated to mechanically remove the reactive deposit clogging the exhaust pipe.
In this vapor-phase growth device, the reactive deposit may attach to the scratching blade, thereby a clogging of the exhaust pipe may occur, eventually. In addition, a clogging may occur at an upstream of the portion where the vapor-phase growth is performed. In a case where the scratching blade is disposed at the upstream, when a reactive deposit attached to the scratching blade falls due to its own weight, a large amount of powder dust may soar, and may reduce a quality of the vapor-phase growth performed at a downstream of the scratching blade. Thus, this vapor-phase growth device is required to prevent a clogging of the gas-inducing pipe while preventing an attachment of the reactive deposit on the scratching blade.